testee hangs with chrome on travis

Here's my [travis configuration](https://github.com/canjs/can-ndjson-stream/blob/cc7318079ffcdc0f142aa651b0b96b680e737136/.travis.yml)

```yaml
sudo: false
dist: trusty
language: node_js
node_js: node
addons:
apt:
packages:
- google-chrome-stable
before_script:
- export DISPLAY=:99.0
- sh -e /etc/init.d/xvfb start &
- sleep 3
```

But the build never exits despite saying the single test has passed: